Generally, the widely-used peripheral input device of a computer system includes for example a mouse, a keyboard, a trackball, or the like. Via the keyboard, the user can directly input characters or symbols into the computer system. As a consequence, most users and most manufacturers of input devices pay much attention to the development of keyboards.
FIG. 1 is a schematic side view illustrating a portion of a conventional keyboard. As shown in FIG. 1, the keyboard 1 comprises a fixing plate 11, a membrane circuit board 12 and plural keys 13. Each key 13 comprises a keycap 131, a scissors-type connecting element 132 and an elastic element 133. The membrane circuit board 12 is disposed over the fixing plate 11. Moreover, the membrane circuit board 12 comprises plural membrane switches 121 corresponding to the plural keys 13.
The elastic element 132 is arranged between the keycap 131 and the membrane circuit board 12. The scissors-type connecting element 132 comprises a first frame 1321 and a second frame 1322. The keycap 131 comprises a first keycap fixing structure 1311 and a second keycap fixing structure 1312. The fixing plate 11 comprises a first fixing structure 111 and a second fixing structure 112. The first fixing structure 111 and the second fixing structure 112 are penetrated upwardly through the membrane circuit board 12. Two ends of the first frame 1321 are connected with the second fixing structure 112 of the fixing plate 11 and the first keycap fixing structure 1311 of the keycap 131, respectively. Two ends of the second frame 1322 are connected with the first fixing structure 111 of the fixing plate 11 and the second keycap fixing structure 1312 of the keycap 131, respectively.
While the keycap 131 of any key 13 is depressed and moved downwardly relative to the fixing plate 11, the first frame 1321 and the second frame 1322 of the scissors-type connecting element 132 are switched from an open-scissors state to a stacked state. Moreover, as the keycap 131 is moved downwardly to compress the elastic element 133, the corresponding membrane switch 121 is pushed by the elastic element 133. Consequently, the keyboard 1 generates a corresponding key signal. When the keycap 131 of the key 13 is no longer depressed, the keycap 131 is moved upwardly relative to the fixing plate 11 in response to an elastic force of the elastic element 133. Meanwhile, the first frame 1321 and the second frame 1322 of the scissors-type connecting element 132 are switched from the stacked state to the open-scissors state again, and the keycap 131 is returned to its original position. The detailed structures and actions of the scissors-type connecting element 132 of the conventional key 13 are well known to those skilled in the art, and are not redundantly described herein.
FIG. 2 is a schematic perspective view illustrating a portion of a conventional notebook computer with a keyboard. As shown in FIG. 2, the notebook computer 2 comprises a base 21, a top cover 22, a rotary shaft 23, a keyboard 1 and a display screen 24. The display screen 24 is installed on the top cover 22. The keyboard 1 is installed on the base 21. The top cover 22 is pivotally coupled with the base 21 through the rotary shaft 23. Consequently, the top cover 22 can be moved relative to the base 21 and changed from an opened position to a closed position in a direction D1, or the top cover 22 can be moved relative to the base 21 and changed from the closed position to the opened position in a direction D2. The structure and function of the keyboard 1 are similar to those of FIG. 1, and are not redundantly described herein.
For facilitating the user to operate the notebook computer 2, the display screen 24 of the notebook computer 2 is a touch screen. Moreover, as the top cover 22 is rotated in a direction toward a rear side of the base 21 through the rotary shaft 23, the top cover 22 is folded to be contacted with a rear surface of the base 21, and the display screen 24 is exposed. Meanwhile, the notebook computer 2 has the outer appearance like a tablet computer. The notebook computer 2 having the appearance of the tablet computer is shown in FIG. 3. Consequently, the display screen 24 can be operated by the user through the user's finger or a touch pen.
However, the keyboard 1 of the notebook computer 2 in the tablet mode is also exposed. When the notebook computer 2 is held by the user's hands, the fingers of the user may erroneously press the keys 13 of the keyboard 1. Since the pressed keys 13 are moved downwardly to form a concave region, it is difficult for the user to stably hold the notebook computer 2. Moreover, if the key 13 is erroneously triggered when the notebook computer 2 is held by the user's hands, the notebook computer 2 generates a key signal. The erroneous operation of the notebook computer 2 usually confuses the user. In other words, the conventional keyboard and the notebook computer with the keyboard need to be further improved.